Color diffusion transfer photographic elements containing a development inhibitor or a precursor thereof are known in the art, as described, for example, in U.S. Pat. No. 3,260,597 to Weyerts et al., U.S. Pat. No. 3,265,498 to Rogers, U.S. Pat. No. 4,009,029 to Hammond et al., Japanese Patent Application (OPI) Nos. 130929/79 to Fushiya et al and 138745/80 to Uemura et al (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). Some of the compounds illustrated in these patents inhibit not only undesired development, but also necessary development, thereby deteriorating the image quality. Some other compounds do not sufficiently release a development inhibitor at an elevated temperature, and therefore cannot sufficiently inhibit an increase in the minimum density and decrease in the sensitivity. Furthermore, particularly when incorporated into a so-called neutralization timing layer in the color diffusion transfer photographic element, these compounds delay the neutralization timing. Such a delay in the neutralization timing deteriorates the sharpness and image quality of transferred color images. Thus, no compounds have heretofore been provided which completely satisfactorily inhibit the increase in the minimum density without lowering the maximum density and deteriorating the image quality of transferred color images.
In particular, the compounds disclosed in the above-described Japanese Patent Application (OPI) No. 138745/80, though containing compounds having a structure somewhat similar to that of the compound of the present invention, do not sufficiently release development inhibitor, and therefore do not sufficiently inhibit the increase in the minimum density at an elevated temperature, as is described in more detail hereinafter.